My New Camera

My New Camera

I’ve been thinking about replacing my 11-year old Konica Minolta Digital SLR for a few months now. The old camera still works okay, but it has issues that started to bother me more and more. The battery door opens on its own, which is annoying. If it hasn’t been used for a while (e.g. a few hours), the first photo taken doesn’t work and the camera has to be power cycled. There are other signs of wear and tear that all add up to a degraded experience. Sure, it works, but not as well as it used to, and certainly not as well as more modern cameras.

Last week I finally pulled the trigger and purchased a Nikon D5500. An incomplete list of the things this camera does better than the old one:

  • The Konica Minolta has 6 megapixels, which is plenty for what I need. The Nikon, with 24 megapixels, probably has more than I need. However, digital sensors have come a long way in a decade. Despite the fact that the Nikon sensor pixels are smaller than the Konica Minolta’s (both cameras have APS-C sensors), the Nikon sensor has much better low-light performance than the Konica Minolta.
  • The Konica Minolta doesn’t have a movie mode, while the Nikon can do 1080P at 60 FPS. I don’t often take movies, but it’s nice to have that feature there if I want it.
  • The Nikon has much faster and better image processing. Of course, this is no Nikon D5 that costs $6,500, but it’s plenty fast for my purposes.
  • The Nikon has a touch screen that has iPhone-like swipe/pinch gestures, and touch-to-focus. As hilarious as it is to see my daughter try to swipe on my old camera, I like the idea of making photography approachable for her.
  • The availability of lenses for Nikon cameras is probably unparalleled. This was a source of consternation for me – let me explain. I have a number of lenses for the Konica Minolta that aren’t necessarily top quality, but they work fine. I have coverage from 18-500mm. In 2006 (shortly after I got my Konica Minolta, natch), Sony bought Konica Minolta’s camera line, and continue to make cameras to this day based on that product line under their name. Sony still makes cameras that are compatible with Konica Minolta lenses (the A-mount system), but recently they have focused most of their innovation towards their E-mount system. I wasn’t sure I wanted to stay with a system that (it looks like to me) Sony isn’t focused on. Sony makes a line of very nice mirrorless cameras that only support the E-mount system. I thought long and hard about buying a Sony mirrorless camera (especially the α6500, $1400 for the body), but in the end I decided I couldn’t justify spending that much money. With a Nikon, I can get a more reasonably priced body and gain access to a wealth of high-quality lenses.
  • The Nikon can be controlled (in a limited fashion) from a smartphone or tablet over Wifi, which seems pretty useful.

Clever readers might wonder why I got a D5500 when Nikon has already announced the follow-on D5600? Well, the D5600 adds very few features over the D5500 (basically only Bluetooth connectivity and slightly better battery life), and I got my D5500 as a fully warrantied refurb for a significant discount. Clever readers might also wonder why I didn’t get something like a Sony α6000/α6300 for $400/$1000? Basically, I had read bad things about the Sony menu system, the α6000/α6300 don’t have a touch screen, and E-mount lenses are rarer and comparatively more expensive than Nikon equivalents.

Finally, here’s a photo using the new camera from this morning’s dog walk. I centered it on the iconic NCAR Mesa Laboratory building. Click for the full 24 megapixel size!

My dog walks have better mountain views than your dog walks
Solar Performance 2016

Solar Performance 2016

Snow makes solar panels sad

We have had solar panels on our house for almost three years. Our DC to AC inverter (which converts solar electrons to wall plug electrons) is connected to the “Internet” (it’s new, you should check it out) and reports energy production information to a “website.” Specifically, this one: SolarEdge Monitoring (there are demo links that anyone can look at without an account). The website collects and presents the data in a few ways, showing current and past production with graphs, and various totals that make a customer feel good about themselves:

Can I get some love, Al Gore?

Customers can download historical data off the website, which I have done and analyzed. The plot below shows how many Watt hours (Wh) the system has produced each of the last three years (check it out, the plot is interactive!). The system was turned on Feb 10, 2014, so it’s no surprise that 2014 has the lowest total. Clearly, 2016 was a much better year than 2015, producing over 8% more energy.

(Mobile users may want to request the desktop version of this page to view the plots: Safari, Chrome)

As an aside, here is a histogram of the daily totals over the life of the system. The peak at 0 Wh is real – those are days when the panels are completely covered in snow. Such is solar panel life in Colorado!

The high total for 2016 got me thinking – just how good of a year was 2016? There are many ways to explore this, and I went with one that I’m familiar with: simulation. Essentially, what I did was for every day between Jan 1, 2016 and Dec 31, 2016, I randomly chose the Wh generated on that same calendar day from all my historical samples, and added them up. For example, if I am looking at July 9, 2016, I have three data points (2014, 2015, and 2016), and I choose one of them with equal chance, and add it to the total. I do this for every day of the year, and I do many thousands of simulated years. Out of this simulation I get a distribution of yearly totals:

The mean result is just a shade over 4,000 KWh. I’ve shown the one, two, and three-sigma regions with decreasing shades of grey. The 2016 total, 4,131 KWh, is well past one sigma, and close to the two sigma value. This indicates that 2016 was indeed a fairly good solar year!

How realistic is this simulation method? 2014 is missing all of January and part of February. In 2015 and 2016, January averaged about 220 KWh. If we take the mean value from simulations of 4,000 KWh, and subtract off 220 KWh, we get 3,780 KWh, which is almost exactly what was recorded for 2014. This is a good piece of evidence that the method might have some validity.

The simulations suggest that 2014 was a normal solar year, and that 2015 (at 3,817 KWh) was a particularly poor solar year. In fact, 2015 was a much worse solar year than 2016 was a good year according to the distributions of simulations.

I’ve put all the code here for your inspection. I didn’t present it here, but in the code I explored a modification to the simulation method that added some “stickiness” to the choice of historical weather performance. My thought was that because day to day weather is highly correlated (tomorrow’s weather is most likely similar to today’s), enforcing some favoritism to stringing together days that actually were sequential might be more realistic. TL;DR: I get almost identical results at the expense of much slower simulations.

Finally, a happy new year to all of you!